2 * Copyright (c) 2016-2019 Cisco and/or its affiliates.
3 * Copyright (c) 2019 Arm Limited
4 * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates.
5 * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
6 * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h).
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at:
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
19 #ifndef __included_ssvm_fifo_h__
20 #define __included_ssvm_fifo_h__
22 #include <vppinfra/clib.h>
23 #include <vppinfra/vec.h>
24 #include <vppinfra/pool.h>
25 #include <vppinfra/format.h>
27 /** Out-of-order segment */
30 u32 next; /**< Next linked-list element pool index */
31 u32 prev; /**< Previous linked-list element pool index */
33 u32 start; /**< Start of segment, normalized*/
34 u32 length; /**< Length of segment */
37 #define SVM_FIFO_TRACE (0)
38 #define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
39 #define SVM_FIFO_INVALID_SESSION_INDEX ((u32)~0)
40 #define SVM_FIFO_INVALID_INDEX ((u32)~0)
41 #define SVM_FIFO_MAX_EVT_SUBSCRIBERS 8
45 SVM_FIFO_NO_TX_NOTIF = 0,
46 SVM_FIFO_WANT_TX_NOTIF = 1,
47 SVM_FIFO_WANT_TX_NOTIF_IF_FULL = 2,
55 } svm_fifo_trace_elem_t;
57 typedef struct svm_fifo_chunk_
61 struct svm_fifo_chunk_ *next;
65 typedef enum svm_fifo_flag_
67 SVM_FIFO_F_SIZE_UPDATE = 1 << 0,
70 typedef struct _svm_fifo
72 CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
73 u32 size; /**< size of the fifo */
74 u32 nitems; /**< usable size(size-1) */
75 u8 flags; /**< fifo flags */
76 svm_fifo_chunk_t *start_chunk;/**< first chunk in fifo chunk list */
77 svm_fifo_chunk_t *end_chunk; /**< end chunk in fifo chunk list */
78 svm_fifo_chunk_t *new_chunks; /**< chunks yet to be added to list */
80 CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
81 volatile u32 has_event; /**< non-zero if deq event exists */
83 u32 master_session_index;
84 u32 client_session_index;
85 u8 master_thread_index;
86 u8 client_thread_index;
89 u32 ct_session_index; /**< Local session index for vpp */
90 u32 freelist_index; /**< aka log2(allocated_size) - const. */
91 i8 refcnt; /**< reference count */
92 struct _svm_fifo *next; /**< next in freelist/active chain */
93 struct _svm_fifo *prev; /**< prev in active chain */
95 CLIB_CACHE_LINE_ALIGN_MARK (consumer);
97 svm_fifo_chunk_t *head_chunk; /**< tracks chunk where head lands */
98 volatile u32 want_tx_ntf; /**< producer wants nudge */
99 volatile u32 has_tx_ntf;
101 CLIB_CACHE_LINE_ALIGN_MARK (producer);
103 svm_fifo_chunk_t *tail_chunk; /**< tracks chunk where tail lands */
105 ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
106 u32 ooos_list_head; /**< Head of out-of-order linked-list */
107 u32 ooos_newest; /**< Last segment to have been updated */
108 volatile u8 n_subscribers;
109 u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
112 svm_fifo_trace_elem_t *trace;
115 svm_fifo_chunk_t default_chunk;
123 typedef struct svm_fifo_segment_
127 } svm_fifo_segment_t;
130 #define svm_fifo_trace_add(_f, _s, _l, _t) \
132 svm_fifo_trace_elem_t *trace_elt; \
133 vec_add2(_f->trace, trace_elt, 1); \
134 trace_elt->offset = _s; \
135 trace_elt->len = _l; \
136 trace_elt->action = _t; \
139 #define svm_fifo_trace_add(_f, _s, _l, _t)
142 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
143 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
145 /* internal function */
147 f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
149 /* load-relaxed: consumer owned index */
151 /* load-acq: consumer foreign index (paired with store-rel in producer) */
152 *tail = clib_atomic_load_acq_n (&f->tail);
155 /* internal function */
157 f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
159 /* load relaxed: producer owned index */
161 /* load-acq: producer foreign index (paired with store-rel in consumer) */
162 *head = clib_atomic_load_acq_n (&f->head);
165 /* producer consumer role independent */
166 /* internal function */
168 f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
170 /* load-acq : consumer foreign index (paired with store-rel) */
171 *tail = clib_atomic_load_acq_n (&f->tail);
172 /* load-acq : producer foriegn index (paired with store-rel) */
173 *head = clib_atomic_load_acq_n (&f->head);
176 /* internal function */
178 f_free_count (svm_fifo_t * f, u32 head, u32 tail)
180 return (f->nitems + head - tail);
183 /* internal function */
185 f_cursize (svm_fifo_t * f, u32 head, u32 tail)
187 return (f->nitems - f_free_count (f, head, tail));
190 /* used by consumer */
192 svm_fifo_max_dequeue_cons (svm_fifo_t * f)
195 f_load_head_tail_cons (f, &head, &tail);
196 return f_cursize (f, head, tail);
199 /* used by producer*/
201 svm_fifo_max_dequeue_prod (svm_fifo_t * f)
204 f_load_head_tail_prod (f, &head, &tail);
205 return f_cursize (f, head, tail);
208 /* use producer or consumer specific functions for perfomance.
209 * svm_fifo_max_dequeue_cons (svm_fifo_t *f)
210 * svm_fifo_max_dequeue_prod (svm_fifo_t *f)
213 svm_fifo_max_dequeue (svm_fifo_t * f)
216 f_load_head_tail_all_acq (f, &head, &tail);
217 return f_cursize (f, head, tail);
220 /* used by producer */
222 svm_fifo_is_full_prod (svm_fifo_t * f)
224 return (svm_fifo_max_dequeue_prod (f) == f->nitems);
227 /* use producer or consumer specific functions for perfomance.
228 * svm_fifo_is_full_prod (svm_fifo_t * f)
229 * add cons version if needed
232 svm_fifo_is_full (svm_fifo_t * f)
234 return (svm_fifo_max_dequeue (f) == f->nitems);
237 /* used by consumer */
239 svm_fifo_is_empty_cons (svm_fifo_t * f)
241 return (svm_fifo_max_dequeue_cons (f) == 0);
244 /* used by producer */
246 svm_fifo_is_empty_prod (svm_fifo_t * f)
248 return (svm_fifo_max_dequeue_prod (f) == 0);
251 /* use producer or consumer specific functions for perfomance.
252 * svm_fifo_is_empty_cons (svm_fifo_t * f)
253 * svm_fifo_is_empty_prod (svm_fifo_t * f)
256 svm_fifo_is_empty (svm_fifo_t * f)
258 return (svm_fifo_max_dequeue (f) == 0);
262 svm_fifo_is_wrapped (svm_fifo_t * f)
265 f_load_head_tail_all_acq (f, &head, &tail);
266 return head % f->size > tail % f->size;
269 /* used by producer*/
271 svm_fifo_max_enqueue_prod (svm_fifo_t * f)
274 f_load_head_tail_prod (f, &head, &tail);
275 return f_free_count (f, head, tail);
278 /* use producer or consumer specfic functions for perfomance.
279 * svm_fifo_max_enqueue_prod (svm_fifo_t *f)
280 * add consumer specific version if needed.
283 svm_fifo_max_enqueue (svm_fifo_t * f)
286 f_load_head_tail_all_acq (f, &head, &tail);
287 return f_free_count (f, head, tail);
291 svm_fifo_has_event (svm_fifo_t * f)
297 svm_fifo_has_ooo_data (svm_fifo_t * f)
299 return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
303 * Sets fifo event flag.
305 * Also acts as a release ordering.
307 * @return 1 if flag was not set.
310 svm_fifo_set_event (svm_fifo_t * f)
312 /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
313 return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
314 return !clib_atomic_swap_rel_n (&f->has_event, 1);
318 * Unsets fifo event flag.
320 * Also acts as an acquire barrier.
323 svm_fifo_unset_event (svm_fifo_t * f)
325 clib_atomic_swap_acq_n (&f->has_event, 0);
328 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
329 void svm_fifo_init (svm_fifo_t * f, u32 size);
330 void svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c);
331 void svm_fifo_free (svm_fifo_t * f);
333 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
334 const u8 * copy_from_here);
335 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
336 u32 required_bytes, u8 * copy_from_here);
337 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
339 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
340 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
341 void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
342 int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
343 void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
344 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
345 void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf);
346 void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
347 void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
348 void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
349 format_function_t format_svm_fifo;
352 * Max contiguous chunk of data that can be read
355 svm_fifo_max_read_chunk (svm_fifo_t * f)
358 u32 head_idx, tail_idx;
359 f_load_head_tail_cons (f, &head, &tail);
360 head_idx = head % f->size;
361 tail_idx = tail % f->size;
362 return tail_idx > head_idx ? (tail_idx - head_idx) : (f->size - head_idx);
366 * Max contiguous chunk of data that can be written
369 svm_fifo_max_write_chunk (svm_fifo_t * f)
372 u32 head_idx, tail_idx;
373 f_load_head_tail_prod (f, &head, &tail);
374 head_idx = head % f->size;
375 tail_idx = tail % f->size;
376 return tail_idx >= head_idx ? (f->size - tail_idx) : (head_idx - tail_idx);
380 * Advance tail pointer
382 * Useful for moving tail pointer after external enqueue.
385 svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
387 ASSERT (bytes <= svm_fifo_max_enqueue_prod (f));
388 /* load-relaxed: producer owned index */
391 /* store-rel: producer owned index (paired with load-acq in consumer) */
392 clib_atomic_store_rel_n (&f->tail, tail);
396 svm_fifo_head (svm_fifo_t * f)
398 /* load-relaxed: consumer owned index */
399 return (f->head_chunk->data
400 + ((f->head % f->size) - f->head_chunk->start_byte));
404 svm_fifo_tail (svm_fifo_t * f)
406 /* load-relaxed: producer owned index */
407 return (f->tail_chunk->data
408 + ((f->tail % f->size) - f->tail_chunk->start_byte));
412 svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
414 f->want_tx_ntf |= ntf_type;
418 svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
420 f->want_tx_ntf &= ~ntf_type;
424 svm_fifo_clear_tx_ntf (svm_fifo_t * f)
426 /* Set the flag if want_tx_notif_if_full was the only ntf requested */
427 f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
428 svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
432 svm_fifo_reset_tx_ntf (svm_fifo_t * f)
438 svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
440 u8 want_ntf = f->want_tx_ntf;
442 if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
444 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
446 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
448 u32 max_deq = svm_fifo_max_dequeue_cons (f);
449 u32 nitems = f->nitems;
450 if (!f->has_tx_ntf && max_deq < nitems
451 && max_deq + n_last_deq >= nitems)
460 svm_fifo_n_subscribers (svm_fifo_t * f)
462 return f->n_subscribers;
465 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
466 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
468 always_inline ooo_segment_t *
469 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
471 if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
473 return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
477 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
479 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
483 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos, u32 tail)
485 return ((pos - tail) % f->size);
489 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos, u32 tail)
491 return ((tail - pos) % f->size);
495 ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
498 /* load-relaxed: producer owned index */
501 return ooo_segment_distance_from_tail (f, s->start, tail);
505 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
510 always_inline ooo_segment_t *
511 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
513 if (s->prev == OOO_SEGMENT_INVALID_INDEX)
515 return pool_elt_at_index (f->ooo_segments, s->prev);
518 always_inline ooo_segment_t *
519 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
521 if (s->next == OOO_SEGMENT_INVALID_INDEX)
523 return pool_elt_at_index (f->ooo_segments, s->next);
526 #endif /* __included_ssvm_fifo_h__ */
529 * fd.io coding-style-patch-verification: ON
532 * eval: (c-set-style "gnu")